Zenith 1 rebuild question

[Fordman92]

I recently bought a new fuel bowl from macs and it has a while I’m not familiar with, any insight on what I’m supposed to do with it?

[MAG]

That is a passage opening that requires a brass plug. Bratton's P/N 14640.
Some folks remove the plugs to clean the passages.

[rotorwrench]

If parts like this come bare. The buyer will need to purchase the missing pieces that can't be transferred from the assembly that it is a replacement part for. All the parts are available if a person knows whereto find them, The part number in the previous post is a plug kit with all needed plugs for the Zenith model A carbs.
https://www.brattons.com/searchprods.asp

[Fordman92]

Thanks, It continues through the threads to the other side, I’m assuming I need to plug both?

[MAG]

Pic of the other side of carb?

[katy]

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Originally Posted by Fordman92

Thanks, It continues through the threads to the other side, I’m assuming I need to plug both?

Just plug the outside, the other end should be in the fuel bowl allowing fuel to get to the GAV.

[Rob Doe]

Over the years there were two different pathways used for the GAV flow. The early path was from the fuel bowl to the GAV and back to the bottom of the compensating well. The later pathway was from the fuel bowl to the GAV and then straight to the bottom of the cap jet. This later pathway appears to be what is shown in the photo.

Late edit: after seeing another photo below, I'm not so sure of which pathway the OP's carb has. The second photo and its lighting appears to possibly have the early path.

[Benson]

Originally Posted by Rob Doe

Over the years there were two different pathways used for the GAV flow. The early path was from the fuel bowl to the GAV and back to the bottom of the compensating well.

The later pathway was from the fuel bowl to the GAV and then straight to the bottom of the main jet, which is directly above the drain plug. This later pathway appears to be what is shown in the photo.

1. I believe that the blue text above should read CAP JET.

And the rest of that sentence should be deleted.

2. The main jet is feed directly from the float bowl on the opposite side of the bowl and does not get extra gas when you open GAV only the CAP jet gets extra gas when GAV is opened.

But it should be noted that when the engine is running above 35 or so that both the MAIN jet and CAP jet supply the gasoline for engine to run. So if you open GAV some more the mixture is "richened" as more gas goes through the CAP jet.

3. Also there is a third brass plug on the bottom of SOME of the early carbs to route gas to CAP jet.

There are two different ways that this was done.

a. One plug/hole came from REAR of carb near the drain.

b. the other method was a hole drilled from the FRONT of carb near the mounting bolt.

Years ago I used to know the routes of the front and rear third plugs but I have since forgotten those details.


I guess that I should go through the pile of lower castings and find one of each type and drill them out and find out how they are routed.

[Rob Doe]

Oh, boy, thanks Benson. You are correct. The path runs direct to the cap jet for sure. My editor is on vacation. LOL Thanks for catching that and I'll edit it correctly.

[Gary WA]

http://modelabasics.com/carb%20basics%202.htm

[Fordman92]

This is how far it goes in.

[Rob Doe]

Originally Posted by Fordman92

This is how far it goes in.

Put the wire in all the way and shine a light down into the intake where the cap jet will be screwed into. I believe you will see your wire there. Or it may be at the bottom of the compensating well. I can't tell which from the picture and the lighting.

[BillCNC]

If that's a new re-pop casting, I would think the plugs would be already installed.

Regards
Bill